This invention pertains to evaporative coolers, particularly to maintaining and repairing the water reservoir of said coolers.
Evaporative coolers are widely employed to cool buildings in areas of the country where the humidity is sufficiently low. These coolers must be cleaned periodically and parts repaired or replaced.
Water is held in the sheet metal base of a cooler, which forms a tray with raised sides to create the reservoir. Water is pumped to the tops of porous pads through which air is drawn and cooled by evaporation. Water not evaporated drains back to the reservoir. A float-activated valve maintains the water level. Residue from contaminates; salts and distilled minerals from the water are collected in the reservoir and must be periodically cleaned out. Contaminates eventually permeate into the plating or galvanization of the metal of the reservoir and corrosion results.
Heretofore, the reservoir would be evacuated, dried, scrapped or brushed, and debris removed. Special attention would be given to badly corroded spots and leaks would be repaired. Once the reservoir is properly prepared, it would then be coated with a submarine cooler emulsion. In extreme cases, said emulsion may not be sufficient to repair said leaks. Numerous disadvantages exist with the use of said emulsion. This is a time-consuming, dirty, toxic task. The clean up after this process is as undesirable as the task itself. These coatings generally require considerable drying time before the cooler can be re-assembled and placed into service. The major disadvantage with this repair method is that where adhesion to the corroded surface of said cooler's reservoir has not been perfect, water leaches under the coating and reaches areas where there is no access for free oxygen and anaerobic corrosion results.
Various prior inventions in addition to said submarine emulsions have been directed to the alleviation of this problem:
U.S. Pat. No. 5,392,944, Jennings, Feb. 28, 1995 describes a tray, which is positioned below the cooler for the purpose of collecting water which leaks through the corroded cooler base. This patent does not relate to the maintenance of the cooler or the prevention of corrosion. It requires that a cooler be dismounted from a roof for installation and addresses only cooler reservoirs that have already rotted through.
U.S. Pat. No. 4,977,755, Tulley, Dec. 18, 1990 describes a liner for the reservoir of both side and downdraft evaporative coolers which is replaceable and has vertical side walls which are folded up and inserted between the pads and the cooler structure to form a seal. This patent fails to address the most critical aspect of corrosion in evaporative cooler reservoirs; anaerobic corrosion. Anaerobic corrosion becomes present when a fluid such as water is presented onto a ferrous element such as the galvanized sheet metal commonly used to form the reservoir of the majority of evaporative coolers in use today, and there is the absence of free oxygen. The liner described in this patent sits directly onto a cooler's existing reservoir eliminating any possibility of free oxygen to enter. When moisture from leaks or internal sweating occurs, an anaerobic environment is created under said liner that can actually exacerbate the corrosive process. The effect is very similar to that described with the use of submarine cooler emulsion.
U.S. Pat. No. 4,687,604, Goettl, Aug. 18, 1987 describes a cooler water reservoir with channels in the base, which localized the water supply and thus requires less water to operate. The reservoir is integral to the cooler and cannot be removed for cleaning or replaced when it becomes corroded.
U.S. Pat. No. 4,657,709, Goettl, Apr. 14, 1997 describes a water distribution trough design of the reservoir, which relieves the water distribution problems associated with large evaporative coolers. It is directed at large industrial size coolers. The troughs are integral to the cooler.
U.S. Pat. No. 4,369,148, Hawkins, Jan. 18, 1983 describes a supplantary reservoir positioned below the cooler in which are performed the functions of maintaining the water level and feeding the pump which serves to deliver water to the tops of the pads. Water is thus not retained in the cooler base and the problems of cleaning and corrosion are thus diverted to the external reservoir, which is more easily removed and serviced.
Provisional Patent Application No. 60,040,108, Rees/McCabe, Mar. 10, 1997 describes a series of trays which are interconnected by the use of small tubes between the trays which are sealed together by the use of rubber grommets. The trays are placed inside the cooler's reservoir forming a square trough around the edges. They can be cleaned or replaced. The problem of anaerobic corrosion as identified with regard to the invention described in U.S. Pat. No. 4,977,755 is present in this art also. Additionally, the interconnecting joints described between the trays are constantly submerged and given to leaking.